Objective: The study aims to identify and analyze the influence of body composition and basal metabolic rate over the behavior of temporal parameters of ground reactive forces during the gait of postmenopausal. Methods: The experimental study was carry out with 52 women (±59.8 years). The fat mass, abdominal visceral adiposity, skeletal muscle mass, fat-free mass and basal metabolic rate have evaluated by octopolar bioimpedance. The data for the ground reactive forces were collect through the force platform. Results: In relative terms, the fat mass showed influence the final phase of support, causing a decrease in this parameter. Abdominal visceral adiposity also exerted inverse influence on the vertical loading (r = -0.31) and unloading (r = -0.35) rate. The skeletal muscle mass (r = -0.45, r = -0.46; p<0.01) and basal metabolic rate (r = -0.44, r = -0.46; p<0.01) influenced the vertical loading rate and the relationship between the vertical rates significantly. Conclusion: The study suggests that the increase on fat mass and abdominal visceral adiposity, influence the support time and the vertical rates. With a more robust skeletal muscle system the postmenopausal women exhibit the phases of the gait cycle less accentuated, signaling less stress on the joints.

Nowadays the underwater gliding after the starts and the turns plays a major role in the overall swimming performance. Hence, minimizing hydrodynamic drag during the underwater phases should be a main aim during swimming. Indeed, there are several postures that swimmers can assume during the underwater gliding, although experimental results were not conclusive concerning the best body position to accomplish this aim. Therefore, the purpose of this study was to analyse the effect in hydrodynamic drag forces of using different body positions during gliding through computational fluid dynamics (CFD) methodology. For this purpose, two-dimensional models of the human body in steady flow conditions were studied. Two-dimensional virtual models had been created: (i) a prone position with the arms extended at the front of the body; (ii) a prone position with the arms placed alongside the trunk; (iii) a lateral position with the arms extended at the front and; (iv) a dorsal position with the arms extended at the front. The drag forces were computed between speeds of 1.6 m/s and 2 m/s in a two-dimensional Fluent(®) analysis. The positions with the arms extended at the front presented lower drag values than the position with the arms aside the trunk. The lateral position was the one in which the drag was lower and seems to be the one that should be adopted during the gliding after starts and turns.

The anaerobic threshold (AnT) seems to be not only a physiologic boundary but also a transition after which swimmers technique changes, modifying their biomechanical behaviour. We expanded the AnT concept to a biophysical construct in the four conventional swimming techniques. Seventy-two elite swimmers performed a 5×200 m incremental protocol in their preferred swimming technique (with a 0.05 m·s-1 increase and a 30 s interval between steps). A capillary blood samples were collected from the fingertip and stroke rate (SR) and length (SL) determined for the assessment of [La], SR and SL vs. velocity inflexion points (using the interception of a pair of linear and exponential regression curves). The [La] values at the AnT were 3.3±1.0, 3.9±1.1, 2.9±1 .34 and 4.5±1.4 mmol·l-1 (mean±SD) for front crawl, backstroke, breaststroke and butterfly, and its corresponding velocity correlated highly with those at SR and SL inflection points (r=0.91-0.99, p<0.001). The agreement analyses confirmed that AnT represents a biophysical boundary in the four competitive swimming techniques and can be determined individually using [La] and/or SR/SL. Blood lactate increase speed can help characterise swimmers' anaerobic behaviour after AnT and between competitive swimming techniques.

The aim of this study was to analyze the effects of depth on drag during the streamlined glide in swimming using Computational Fluid Dynamics. The Computation Fluid Dynamic analysis consisted of using a three-dimensional mesh of cells that simulates the flow around the considered domain. We used the K-epsilon turbulent model implemented in the commercial code Fluent(®) and applied it to the flow around a three-dimensional model of an Olympic swimmer. The swimmer was modeled as if he were gliding underwater in a streamlined prone position, with hands overlapping, head between the extended arms, feet together and plantar flexed. Steady-state computational fluid dynamics analyses were performed using the Fluent(®) code and the drag coefficient and the drag force was calculated for velocities ranging from 1.5 to 2.5 m/s, in increments of 0.50m/s, which represents the velocity range used by club to elite level swimmers during the push-off and glide following a turn. The swimmer model middle line was placed at different water depths between 0 and 1.0 m underwater, in 0.25m increments. Hydrodynamic drag decreased with depth, although after 0.75m values remained almost constant. Water depth seems to have a positive effect on reducing hydrodynamic drag during the gliding. Although increasing depth position could contribute to decrease hydrodynamic drag, this reduction seems to be lower with depth, especially after 0.75 m depth, thus suggesting that possibly performing the underwater gliding more than 0.75 m depth could not be to the benefit of the swimmer.

Over the past decade, CrossFit has become established as both a popular form of high-intensity strength and conditioning training and a growing competitive sport. Despite its global diffusion, uncertainties remain regarding the main physiological and biomechanical determinants of performance, particularly when accounting for sex and training experience. This doctoral thesis aimed to provide an integrated analysis of CrossFit’s physiological and biomechanical demands and to explore potential performance predictors in recreational athletes. Three studies were conducted: i) a systematic review on physiological and biomechanical demands; ii) an experimental analysis of the associations between physiological and biomechanical variables and WOD performance; and iii) an examination of how sex and training experience modulate these relationships. The findings indicated that WODs elicit high cardiovascular, metabolic, and neuromuscular demands, yet the literature remains heterogeneous and lacks consensus on key performance determinants. Data revealed moderate, exploratory associations between performance and variables such as maximal strength, jumping power, ventilation, oxygen consumption, and post-exercise blood lactate, with these relationships differing by sex and experience. Men appeared to rely more on strength and power, whereas women were more influenced by physiological responses and perceived exertion. Training experience was linked to faster completion times, likely due to greater technical proficiency and effort regulation. Overall, the results highlight the multifactorial nature of CrossFit performance and the need for individualized training approaches based on physiological, biomechanical, and experiential characteristics.

In Swimming, there are numerous factors that influence performance, where hydrodynamic effects play a key-role. Hydrodynamics in swimming include resistance forces (drag) and propulsive forces. Due to all its complexity, hydrodynamics is one of the most studied areas in swimming. Drag has been extensively studied in swimming. Therefore, the first objective was to better understand how resistive forces are measured with a focus on active drag since swimmers spend of the race swimming. There are experimental and numerical methods to measure or estimate drag. Of all the existing methods for measuring drag, there is no gold standard. Indeed, all studies that compared methods reached the same conclusion: they all measure the same phenomenon despite differences among them. This may occur due to the characteristics of each method. A secondary objective was to use an equipment that collects propulsive data and understand the relationship of propulsive force with other swimming determinants. This is an equipment that is simple to use and understand, with the possibility of being used in a training context. It consists in a wireless sensor that also provides the trajectory of the hand. This way, it was possible to understand at what point of the arm-pull swimmers generate greater forces. All this information is acquired in real time through a mobile application that transmits the swimmers' outputs. In this study, swimming speed, propulsive force and other kinematic and kinetic variables did not change significantly (p < 0.05) between sections (only the intracyclic fluctuation of swimming speed decreased significantly, p = 0.005). Realizing that swimming speed was determined by the interaction of kinematic and kinetic variables, specifically by propulsive force and active drag coefficient. The third objective was to understand and explain the relevance of using the drag coefficient in hydrodynamic studies. Seeking to improve the efficiency and performance of swimmers, allowing the identification of areas for improvement in swimming technique and the development of more effective training strategies. The drag coefficient can be calculated based on the value of force, obtained by both drag and propulsion, providing a crucial measure to understand and optimize the interaction between the swimmer and the water during swimming. It is possible to see that swimmers have a greater active drag coefficient than the passive one, but with a strong agreement between them. Greater active than passive drag can probably be due to the larger frontal surface area during active conditions. Active coefficient data appears to be a more absolute indicator of drag for determining a hydrodynamic profile. Better than studying isolated cases of propulsion or drag.

Although performance and biomechanical evaluations are becoming more swimming-specific, dryland testing permits monitoring of a larger number of performance-related variables. However, as the degree of comparability of measurements conducted in-water and on land conditions is unclear, we aimed to assess the differences between force production in these two different conditions. Twelve elite swimmers performed a 30 s tethered swimming test and four isokinetic tests (shoulder and knee extension at 90 and 300°/s) to assess peak force, peak and average torque, and power symmetry index. We observed contralateral symmetry in all the tests performed, e.g., for 30 s tethered swimming and peak torque shoulder extension at 90°/s: 178 ± 50 vs. 183 ± 56 N (p = 0.38) and 95 ± 37 vs. 94 ± 35 N × m (p = 0.52). Moderate to very large direct relationships were evident between dryland testing and swimming force production (r = 0.62 to 0.96; p < 0.05). Swimmers maintained similar symmetry index values independently of the testing conditions (r = -0.06 to -0.41 and 0.04 to 0.44; p = 0.18-0.88). Asymmetries in water seems to be more related to technical constraints than muscular imbalances, but swimmers that displayed higher propulsive forces were the ones with greater force values on land. Thus, tethered swimming and isokinetic evaluations are useful for assessing muscular imbalances regarding propulsive force production and technical asymmetries.

Mechanical load has been estimated during step exercise based on ground reaction force (GRF) obtained by force platforms. It is not yet accurately known whether these measures reflect foot contact forces once the latter depend on footwear and are potentially modified by the compliant properties of the step bench. The aim of the study was to compare maximal and mean plantar pressure (PP), and maximal GRF obtained by pressure insoles after performing seven movements both over two metal force platforms and over the step bench. Fifteen step-experienced females performed the movements at the cadences of 130 and 140 beats per minute. PP and GRF (estimated from PP) obtained for each floor condition were compared. Maximal PP ranged from 29.27 +/- 9.94 to 47.07 +/- 12.88 N/cm2 as for metal platforms, and from 28.20 +/- 9.32 to 43.00 +/- 13.80 N/cm2 as for the step bench. Mean PP ranged from 11.09 +/- 1.62 to 14.32 +/- 2.06 N/cm2 (platforms) and from 10.71 +/- 1.54 to 14.22 +/- 1.77 N/cm2 (step bench). GRF (normalized body weight) ranged from 1.43 +/- 0.14 to 2.41 +/- 0.24 BW (platforms) and from 1.38 +/- 0.14 to 2.36 +/- 0.19 BW (step bench). No significant statistical differences were obtained for most of the comparisons between the two conditions tested. The results suggest that metal force platform surfaces are suitable to assess mechanical load during this physical activity. The forces applied to the foot are similar to the softer step bench and the hard force platform surface. This may reflect the ability of the performers to adapt their movement patterns to normalize the impact forces in different floor conditions.

During pregnancy women experience several changes in the body’s physiology, morphology, and hormonal system. These changes may affect the balance and body stability and can cause discomfort and pain. The adaptations of the musculoskeletal system due to morphological changes during pregnancy are not fully understood. Few studies clarify the biomechanical changes of gait that occur during pregnancy and in postpartum period.Purposes. The purpose of this review was to analyze the available evidence on the biomechanical adaptations of gait that occur throughout pregnancy and in postpartum period, specifically with regard to the temporal, spatial, kinematic, and kinetic parameters of gait.Methods. Three databases were searched and 9 studies with a follow-up design were retrieved for analysis.Results. Most studies performed temporal, spatial, and kinematic analysis. Only three studies performed kinetic analysis.Conclusion. The adaptation strategies to the anatomical and physiological changes throughout pregnancy are still unclear, particularly in a longitudinal perspective and regarding kinetic parameters.

Na técnica de bruços, apesar das oscilações verticais das partes do corpo (vértex, ombros, anca, joelhos e tornozelos) serem identificadas como características da performance dos nadadores de elite, há poucos trabalhos que quantifiquem a magnitude dessas oscilações, e as relações temporais entre elas. Sanders et al. (1993, 1995, 1998) procurou investigar as características ondulatórias da técnica de bruços, nomeadamente o deslocamento da onda no sentido cefálo-caudal, retirando algumas conclusões nomeadamente: que a percentagem de força contida na frequência fundamental do vértex da cabeça e dos ombros aumenta, à medida que os nadadores alteram a sua técnica de um estilo convencional para uma acção ondulatória, e que os nadadores com melhores performances, ondulam a sua anca espontaneamente, ao qual está relacionado com a redução do movimento vertical do CM.O autor verificou também que nas técnicas com características ondulatórias se deve dar especial ênfase à direcção de propagação de onda ao longo do corpo durante o nado, sendo fundamental a realização de estudos para determinar a frequência, a amplitude e as características das fases da ondulação vertical do vértex da cabeça, ombros, ancas, joelhos e tornozelos de modo a conseguir verificar que a onda se desloca ao longo do corpo, numa direcção céfalo-caudal. Neste âmbito,o objectivo deste estudo consistiu em analisar as características das componentes do movimento ondulatório na técnica de bruços e a sua influência na eficácia de nado, em duas condições de nado, bruços com snorkel(BR) e bruços sem snorkel(SNK), ou seja, pretendemos verificar em que medida é que através da utilização do snorkel, a técnica de nado (bruços) sofre alterações, e quais as repercussões na onda céfalo-caudal. A amostra foi constituída por 8 nadadores portugueses do género masculino, especialistas na técnica de bruços, com elevado nível competitivo (21.25± 6.73 anos; 71.14± 12.39 kg; altura:1.77±0.03 cm; envergadura: 1.84 ± 0.03 cm; %MG: 14.89±6.41). Recolheram-se imagens de duplo meio, para posterior digitalização e processamento através do APAS. Foi aplicada a análise de Fourier para detectar a existência de uma onda céfalo caudal e os respectivos Análise das Características Ondulatórias da Técnica de Bruços- Comparação entre Bruços com e sem snorkel 2010 ESDRM Mestrado em Desporto especialização em Treino Desportivo IV valores de ondulação e o número de Strouhal(St), que consiste num número adimensional que permite descrever um padrão de movimento oscilatório, com base na frequência gestual(Hz) multiplicada pela amplitude dos MI(dada pelo tornozelo) e dividida pela velocidade de nado. O valor para o número de Strouhal encontrado para a nossa amostra foi de 0.41 em BR e 0.53 para SNK valor semelhante ao correspondente à maior eficiência do movimento para peixes e golfinhos, o que poderá corresponder a movimentos ondulatórios do corpo mais próximos daqueles que são apresentados pelos peixes e golfinhos e mais eficientes. Em média, os nadadores, durante um ciclo completo de MS, percorrem uma distância de 1.47 m.c -1 (DP=0.44) na condição BR e 1.22 m.c -1 (DP=0.44) na condição SNK , com uma frequência gestual de 43.32 ciclos por unidade de tempo (DP=9.21) em BR e 45.34 ciclos por unidade de tempo em SNK e um índice de nado correspondente a 1.56 em BR e 1.19 em SNK. Na frequência fundamental de Fourier (H1), a frequência apresenta valores próximos de 0.76 Hz para todos os nadadores em BR e 0.78 Hz em SNK, ou seja, em cada segundo apenas está apresentada 0.76 ou 0.78 partes de uma oscilação. Em H2, a frequência apresenta valores médios de 1.52 Hz em BR e 1.56 Hz em SNK. A amplitude média de ondulação na condição BR é superior á condição SNK excepto no segmento corporal referente ao dedo do pé (0.14 m BR e 0.15m SNK). Em BR os valores de amplitude média mais elevado encontram-se no vértex (0.72m) e cervical(0.32m), tal como na condição SNK, vértex(0.71m) e cervical(0.28m). Uma elevada percentagem da potência total da onda, está contida na frequência fundamental de Fourier (H1) para o ombro, cervical, joelho e tronco na condição BR e para a cervical, ombro e joelho na condição SNK, o que poderá significar que a amplitude da cervical até ao joelho, correspondem a fases importantes para o movimento sinusoidal.